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<meta name="description" content="44年前我们把人送上月球，但在CSS中我们仍然不能很好实现垂直居中——@James Anderson  让一个元素水平居中对于CSS来说非常简单：如果是一个内联元素，我们可以在他的父元素上设置text-align:center;，如果是一个块元素，我们可以使用margin:auto;。然而，只要一想到让一个元素垂直居中，让人死的心都有了。 多年来，垂直居中已成为CSS的不朽神话，也是前端专业人士">
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<meta property="og:description" content="44年前我们把人送上月球，但在CSS中我们仍然不能很好实现垂直居中——@James Anderson  让一个元素水平居中对于CSS来说非常简单：如果是一个内联元素，我们可以在他的父元素上设置text-align:center;，如果是一个块元素，我们可以使用margin:auto;。然而，只要一想到让一个元素垂直居中，让人死的心都有了。 多年来，垂直居中已成为CSS的不朽神话，也是前端专业人士">
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<meta name="twitter:description" content="44年前我们把人送上月球，但在CSS中我们仍然不能很好实现垂直居中——@James Anderson  让一个元素水平居中对于CSS来说非常简单：如果是一个内联元素，我们可以在他的父元素上设置text-align:center;，如果是一个块元素，我们可以使用margin:auto;。然而，只要一想到让一个元素垂直居中，让人死的心都有了。 多年来，垂直居中已成为CSS的不朽神话，也是前端专业人士">



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          <h2 class="post-title" itemprop="name headline">CSS实现水平垂直居中</h2>
        

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<p>44年前我们把人送上月球，但在CSS中我们仍然不能很好实现垂直居中——@James Anderson</p>
</blockquote>
<p>让一个元素水平居中对于CSS来说非常简单：如果是一个内联元素，我们可以在他的父元素上设置<code>text-align:center;</code>，如果是一个块元素，我们可以使用<code>margin:auto;</code>。然而，只要一想到让一个元素垂直居中，让人死的心都有了。</p>
<p>多年来，垂直居中已成为CSS的不朽神话，也是前端专业人士群体中的一个内部笑话。原因是：</p>
<ul>
<li>经常需要使用</li>
<li>理论上看上去非常简单</li>
<li>过去实战中要实现是极其困难，特别是元素大小固定时</li>
</ul>
<a id="more"></a>
<h2 id="方法一：绝对定位"><a href="#方法一：绝对定位" class="headerlink" title="方法一：绝对定位"></a>方法一：绝对定位</h2><h3 id="实现过程"><a href="#实现过程" class="headerlink" title="实现过程"></a>实现过程</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"container"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">h2</span>&gt;</span>完全居中--1.绝对定位<span class="tag">&lt;/<span class="name">h2</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"center"</span>&gt;</span></span><br><span class="line">    内容盒子</span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.container</span>&#123;</span><br><span class="line">  <span class="attribute">position</span>:relative;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">200px</span>;</span><br><span class="line">  <span class="attribute">width</span>: <span class="number">400px</span>;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(0,0,255,0.2);</span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.center</span>&#123;</span><br><span class="line">  <span class="attribute">height</span>: <span class="number">100px</span>;</span><br><span class="line">  <span class="attribute">width</span>: <span class="number">100px</span>;</span><br><span class="line">  <span class="attribute">position</span>:absolute;</span><br><span class="line">  <span class="attribute">margin</span>:auto;</span><br><span class="line">  <span class="attribute">top</span>:<span class="number">0</span>;<span class="attribute">left</span>:<span class="number">0</span>;<span class="attribute">bottom</span>:<span class="number">0</span>;<span class="attribute">right</span>:<span class="number">0</span>;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,255,0,1);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>参见 <a href="https://codepen.io/zxlg/pen/xXRadp" target="_blank" rel="noopener">DEMO:完全居中–1.绝对定位</a></p>
<h2 id="方法二：绝对定位-负margin"><a href="#方法二：绝对定位-负margin" class="headerlink" title="方法二：绝对定位+负margin"></a>方法二：绝对定位+负margin</h2><p>这或许是最常用的方法。如果知道了各个元素的大小，设置等于宽高一半大小的负<code>margin</code>值（如果没有使用<code>box-sizing: border-box</code>样式，还需要加上<code>padding</code>值），再配合<code>top: 50%</code>; <code>left: 50%;</code>样式就会使块元素居中。</p>
<p>给容器设置绝对定位（<code>position:absolute</code>）,并且定位高度（<code>top:50%</code>）和<code>margin-top</code>为高度的一半（<code>margin-top:-height/2</code>），宽度设置类似。</p>
<p>这就意味着使用这种方法来实现垂直居中的效果，那么元素必须要有一个固定的高度。这样一来，给元素设置了固定高度，如果又设置了<code>overflow:auto</code>，那么当元素内容超过容器后，这样元素的就会出现滚动，而不会自适应内容的高度。</p>
<h3 id="实现过程-1"><a href="#实现过程-1" class="headerlink" title="实现过程"></a>实现过程</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"container"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">h2</span>&gt;</span>完全居中--2.绝对定位+负margin值<span class="tag">&lt;/<span class="name">h2</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"center"</span>&gt;</span></span><br><span class="line">    内容盒子</span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.container</span>&#123;</span><br><span class="line">  <span class="attribute">position</span>:relative;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">200px</span>;</span><br><span class="line">  <span class="attribute">width</span>: <span class="number">400px</span>;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(0,0,255,0.2);</span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.center</span>&#123;</span><br><span class="line">  <span class="attribute">height</span>: <span class="number">100px</span>;</span><br><span class="line">  <span class="attribute">width</span>: <span class="number">100px</span>;</span><br><span class="line">  <span class="attribute">position</span>:absolute;</span><br><span class="line">  <span class="attribute">top</span>: <span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">margin-top</span>:-<span class="number">50px</span>;</span><br><span class="line">  <span class="attribute">left</span>: <span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">margin-left</span>:-<span class="number">50px</span>;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,255,0,1);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>如果使用<a href="https://developer.mozilla.org/en-US/docs/Web/CSS/calc" target="_blank" rel="noopener">CSS3中的<code>calc()</code></a>可以减少两个样式：<br><figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.center</span>&#123;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">100px</span>;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">100px</span>;</span><br><span class="line">  <span class="attribute">position</span>:absolute;</span><br><span class="line">  <span class="attribute">top</span>:<span class="built_in">calc</span>(50% - 50px);<span class="comment">/* calc中的`+` `-` 必须被空格包围，`*` `/` 则不需要*/</span></span><br><span class="line">  <span class="attribute">left</span>:<span class="built_in">calc</span>(50% - 50px);</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,255,0,1);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure></p>
<p>参见<a href="https://codepen.io/zxlg/pen/wroRMb" target="_blank" rel="noopener">DEMO:完全居中–2.绝对定位+负margin值</a></p>
<h3 id="优点"><a href="#优点" class="headerlink" title="优点"></a>优点</h3><ul>
<li>浏览器兼容性非常好，甚至支持IE6-7</li>
<li>需要的编码量很少<h3 id="缺点"><a href="#缺点" class="headerlink" title="缺点"></a>缺点</h3></li>
<li>这是个非响应式的方法，不能使用百分比的大小，也不能设置<code>min-/max-</code>的最大值最小值。</li>
<li>内容可能会超出容器</li>
<li>需要为<code>padding</code>预留空间，或者需要使用<code>box-sizing: border-box</code>样式。</li>
</ul>
<h2 id="方法三：模拟表格"><a href="#方法三：模拟表格" class="headerlink" title="方法三：模拟表格"></a>方法三：模拟表格</h2><p>这种可能是最好的方法，因为高度可以随内容改变，浏览器支持也不差。主要缺陷是会产生额外的标签，每一个需要居中的元素需要三个额外的HTML标签。</p>
<h3 id="实现过程-2"><a href="#实现过程-2" class="headerlink" title="实现过程"></a>实现过程</h3><p>设置父元素<code>display:table</code>，子元素<code>display:table-cell; vertical-align:middle</code><br><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"table"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"table-cell"</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"content"</span>&gt;</span>完全居中--3.模拟表格<span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure></p>
<figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.table</span>&#123;</span><br><span class="line">  <span class="attribute">display</span>:table;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">600px</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">300px</span>;</span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.table-cell</span>&#123;</span><br><span class="line">  <span class="attribute">display</span>:table-cell;</span><br><span class="line">  <span class="attribute">vertical-align</span>: middle;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,0,0,0.3); </span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.content</span>&#123;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">margin</span>:<span class="number">0</span> auto; </span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(0,255,0,0.5); </span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>参见<a href="https://codepen.io/zxlg/pen/KXNrpG" target="_blank" rel="noopener">DEMO:完全居中–3.模拟表格</a></p>
<h3 id="优点-1"><a href="#优点-1" class="headerlink" title="优点"></a>优点</h3><ul>
<li>内容高度可变</li>
<li>内容溢出则能自动撑开父元素高度</li>
<li>浏览器兼容性好</li>
</ul>
<h3 id="缺点-1"><a href="#缺点-1" class="headerlink" title="缺点"></a>缺点</h3><ul>
<li>需要额外的HTML标签</li>
</ul>
<h2 id="方法四：inline-box"><a href="#方法四：inline-box" class="headerlink" title="方法四：inline-box"></a>方法四：inline-box</h2><p>基本方法是使用<code>display: inline-block</code>,<code>vertical-align: middle</code>样式和伪元素让内容块在容器中居中。</p>
<h3 id="实现过程-3"><a href="#实现过程-3" class="headerlink" title="实现过程"></a>实现过程</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"container"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">h2</span>&gt;</span>完全居中--4.inline-block<span class="tag">&lt;/<span class="name">h2</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"center"</span>&gt;</span></span><br><span class="line">    内容盒子</span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.container</span>&#123;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">600px</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">200px</span>;</span><br><span class="line">  <span class="attribute">text-align</span>:center;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(0,0,255,0.2);</span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.center</span>&#123;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">display</span>:inline-block;</span><br><span class="line">  <span class="attribute">vertical-align</span>:middle;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,255,0,1);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>参见<a href="https://codepen.io/zxlg/pen/qPqLeQ" target="_blank" rel="noopener">完全居中–4.inline-block</a></p>
<h3 id="优点-2"><a href="#优点-2" class="headerlink" title="优点"></a>优点</h3><ul>
<li>内容高度可变</li>
<li>内容溢出则能自动撑开父元素高度</li>
<li>浏览器兼容性好，甚至可以调整支持IE7<h3 id="缺点-2"><a href="#缺点-2" class="headerlink" title="缺点"></a>缺点</h3></li>
<li>需要额外容器</li>
<li>依赖于<code>margin-left: -0.25em</code>的样式，做到水平居中，需要为不同的字体大小作调整<br>内容区声明的宽度不能大于容器的100% 减去0.25em的宽度</li>
</ul>
<h2 id="方法五：transform-CSS3"><a href="#方法五：transform-CSS3" class="headerlink" title="方法五：transform(CSS3)"></a>方法五：transform(CSS3)</h2><p>为内容指定带有厂商前缀的<code>transform: translate(-50%,-50%)</code>和<code>top: 50%; left: 50%;</code>样式就可以让内容块居中。</p>
<h3 id="实现过程-4"><a href="#实现过程-4" class="headerlink" title="实现过程"></a>实现过程</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"container"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">h2</span>&gt;</span>完全居中--5.transform<span class="tag">&lt;/<span class="name">h2</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"center"</span>&gt;</span></span><br><span class="line">    内容盒子</span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.container</span>&#123;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">600px</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">200px</span>;</span><br><span class="line">  <span class="attribute">position</span>:relative;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(0,0,255,0.2);</span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.center</span>&#123;</span><br><span class="line">  <span class="attribute">position</span>:absolute;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">top</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">left</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">-webkit-transform</span>: <span class="built_in">translate</span>(-50%,-50%);</span><br><span class="line">      <span class="attribute">-ms-transform</span>: <span class="built_in">translate</span>(-50%,-50%);</span><br><span class="line">          <span class="attribute">transform</span>: <span class="built_in">translate</span>(-50%,-50%);</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,255,0,1);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p>参见<a href="https://codepen.io/zxlg/pen/yzVZap" target="_blank" rel="noopener">DEMO:完全居中–5.transform</a></p>
<h3 id="优点-3"><a href="#优点-3" class="headerlink" title="优点"></a>优点</h3><ul>
<li>内容高度可变</li>
<li>代码量小<h3 id="缺点-3"><a href="#缺点-3" class="headerlink" title="缺点"></a>缺点</h3></li>
<li>不支持IE8</li>
<li>需要写厂商前缀</li>
<li>会和其他<code>transform</code>样式有冲突</li>
<li>某些情况下的边缘和字体渲染会有问题</li>
</ul>
<h2 id="方法六：flex-CSS3"><a href="#方法六：flex-CSS3" class="headerlink" title="方法六：flex(CSS3)"></a>方法六：flex(CSS3)</h2><p>CSS未来发展的方向就是采用Flexbox这种设计，解决像垂直居中这种共同的问题。请注意，Flexbox有不止一种办法居中，他也可以用来分栏，并解决奇奇怪怪的布局问题。</p>
<h3 id="实现过程-5"><a href="#实现过程-5" class="headerlink" title="实现过程"></a>实现过程</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"container"</span>&gt;</span></span><br><span class="line"><span class="comment">&lt;!--   &lt;h2&gt;完全居中--5.flex&lt;/h2&gt; --&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span> <span class="attr">class</span>=<span class="string">"center"</span>&gt;</span></span><br><span class="line">    内容盒子</span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<figure class="highlight css"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br></pre></td><td class="code"><pre><span class="line"><span class="selector-class">.container</span>&#123;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">600px</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">200px</span>;</span><br><span class="line">  <span class="attribute">display</span>: -webkit-box;</span><br><span class="line">  <span class="attribute">display</span>: -moz-box;</span><br><span class="line">  <span class="attribute">display</span>: -ms-flexbox;</span><br><span class="line">  <span class="attribute">display</span>: -webkit-flex;</span><br><span class="line">  <span class="attribute">display</span>: flex;</span><br><span class="line"></span><br><span class="line">  <span class="attribute">-webkit-box-align</span>: center;</span><br><span class="line">     <span class="attribute">-moz-box-align</span>: center;</span><br><span class="line">     <span class="attribute">-ms-flex-align</span>: center;</span><br><span class="line">  <span class="attribute">-webkit-align-items</span>: center;</span><br><span class="line">          <span class="attribute">align-items</span>: center;</span><br><span class="line"></span><br><span class="line">  <span class="attribute">-webkit-box-pack</span>: center;</span><br><span class="line">     <span class="attribute">-moz-box-pack</span>: center;</span><br><span class="line">     <span class="attribute">-ms-flex-pack</span>: center;</span><br><span class="line">  <span class="attribute">-webkit-justify-content</span>: center;</span><br><span class="line">          <span class="attribute">justify-content</span>: center;</span><br><span class="line"></span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(0,0,255,0.2);</span><br><span class="line">&#125;</span><br><span class="line"><span class="selector-class">.center</span>&#123;</span><br><span class="line">  <span class="attribute">width</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">height</span>:<span class="number">50%</span>;</span><br><span class="line">  <span class="attribute">background-color</span>: <span class="built_in">rgba</span>(255,255,0,1);</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<h3 id="优点-4"><a href="#优点-4" class="headerlink" title="优点"></a>优点</h3><ul>
<li>内容可以是任意高宽，溢出也能表现良好</li>
<li>可以用于各种高级布局技巧<h3 id="缺点-4"><a href="#缺点-4" class="headerlink" title="缺点"></a>缺点</h3></li>
<li>不支持IE8-9</li>
<li>需要在<code>body</code>上写样式，或者需要额外容器</li>
<li>需要各种厂商前缀兼容现代浏览器</li>
<li>可能有潜在的性能问题</li>
</ul>
<h2 id="完全居中对照表"><a href="#完全居中对照表" class="headerlink" title="完全居中对照表"></a>完全居中对照表</h2><table>
<thead>
<tr>
<th style="text-align:center">所用样式</th>
<th style="text-align:center">支持的浏览器</th>
<th style="text-align:center">是否响应式</th>
<th style="text-align:center">内容溢出后的样式</th>
<th style="text-align:center">resize:both</th>
<th style="text-align:center">高度可变</th>
<th style="text-align:center">主要缺陷 </th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align:center">absolute</td>
<td style="text-align:center">现代浏览器&amp;IE8+</td>
<td style="text-align:center">是</td>
<td style="text-align:center">会导致容器溢出</td>
<td style="text-align:center">是</td>
<td style="text-align:center">是*</td>
<td style="text-align:center">‘可变高度’的特性不能跨浏览器</td>
</tr>
<tr>
<td style="text-align:center">负margin值</td>
<td style="text-align:center">所有</td>
<td style="text-align:center">否</td>
<td style="text-align:center">带滚动条</td>
<td style="text-align:center">大小改变后不再居中</td>
<td style="text-align:center">否</td>
<td style="text-align:center">不具有响应式特性，margin值必须经过手工计算</td>
</tr>
<tr>
<td style="text-align:center">transform</td>
<td style="text-align:center">现代浏览器&amp;IE9+</td>
<td style="text-align:center">是</td>
<td style="text-align:center">会导致容器溢出</td>
<td style="text-align:center">是</td>
<td style="text-align:center">是</td>
<td style="text-align:center">妨碍渲染</td>
</tr>
<tr>
<td style="text-align:center">table-cell</td>
<td style="text-align:center">现代浏览器&amp;IE8+</td>
<td style="text-align:center">是</td>
<td style="text-align:center">撑开容器</td>
<td style="text-align:center">否</td>
<td style="text-align:center">是</td>
<td style="text-align:center">会加上多余的标记</td>
</tr>
<tr>
<td style="text-align:center">inline-block</td>
<td style="text-align:center">现代浏览器&amp;IE8+&amp;IE7*</td>
<td style="text-align:center">是</td>
<td style="text-align:center">撑开容器</td>
<td style="text-align:center">否</td>
<td style="text-align:center">是</td>
<td style="text-align:center">需要使用容器包裹和hack式的样式</td>
</tr>
<tr>
<td style="text-align:center">flex</td>
<td style="text-align:center">现代浏览器&amp;IE10+</td>
<td style="text-align:center">是</td>
<td style="text-align:center">会导致容器溢出</td>
<td style="text-align:center">是</td>
<td style="text-align:center">是</td>
<td style="text-align:center">需要使用容器包裹和厂商前缀（vendor prefix）</td>
</tr>
</tbody>
</table>
<h2 id="参考文献"><a href="#参考文献" class="headerlink" title="参考文献"></a>参考文献</h2><ul>
<li><a href="http://blog.jobbole.com/46574/" target="_blank" rel="noopener">如何只用CSS做到完全居中</a></li>
<li><a href="https://www.w3cplus.com/css3/css-secrets/vertical-centering.html" target="_blank" rel="noopener">CSS秘密花园： 垂直居中</a></li>
</ul>

      
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